1. Field of the Invention
Embodiments described herein generally relate to a precursor source canister, also known as an ampoule, for providing a precursor material to a processing chamber. More particularly, to an ampoule capable of providing a liquid precursor material and/or a vaporized solid precursor material to the processing chamber.
2. Description of the Related Art
Chemical vapor deposition (CVD) and atomic layer deposition (ALD) are known techniques for forming a layer or layers of a material on a substrate, such as a semiconductor wafer. The material is generally formed by the reaction of vapor phase chemicals on and/or near the surface of the substrate. Typically, CVD and ALD processes involve the delivery of gaseous reactants to the substrate surface where a chemical reaction takes place under temperature and pressure conditions favorable to the thermodynamics of the reaction. The type, composition, deposition rate, and thickness uniformity of the materials that may be formed using a conventional CVD or ALD processes are generally limited by the ability to deliver chemical reactants or precursors to the substrate surface.
The precursors may originate from either a liquid precursor material or a solid precursor material. Generally, the liquid precursor material is provided to the processing chamber by a vaporizer, which generates a vapor phase precursor from the liquid precursor material and delivers the vapor phase material to the processing chamber. Solid precursor materials are typically heated and pressurized to sublimate the solid precursor material into a vapor phase precursor material, which is delivered to the processing chamber using a carrier gas.
Various conventional devices are commercially available for delivery of precursors to the substrate surface and typically have the form of a sealed canister, also known as an ampoule. The liquid or solid precursor material is provided to the canister and heated and/or pressurized to provide liquid or vapor to the processing chamber.
However, the conventional devices are typically configured solely for either liquid injection or vapor draw, and are not easily adapted to function for both liquid and solid precursor source materials. Thus, if a user needs to convert from a solid precursor material to a liquid precursor material, or vice versa, the ampoule must be changed. This results in at least two ampoules per processing chamber, which results in higher capital outlay for multiple ampoules. Also, the time required to remove and replace ampoules decreases throughput. Further, the conventional devices typically lack a sensor to accurately and continuously determine and monitor precursor source material levels within the ampoule.
Therefore, there is a need for an improved ampoule suitable for use with both liquid and solid precursor materials having a continuous level sensor.